Building Disaster Recovery Serviceguard Solutions Using Metrocluster with Continuous Access EVA A.05.01

1. After all Continuous Access links fail, put the Continuous Access link state to suspend mode
by using HP P6000 Command View UI. When Continuous Access link is in suspend state, HP
P6000/EVA Continuous Access does not resynchronize the source and destination Vdisks
upon links recovery. This helps in maintaining data consistency.
2. Take a local replication copy of the destination Vdisks using HP P6000 Business Copy software
so that there is consistent copy available for recovery.
3. Change the Continuous Access link state to resume mode. This initiates the normalization upon
Continuous Access link recovery.
The above steps ensures that even though the primary site fails while copy is in progress, the
destination Vdisk can be used after restoring the data from the BC volume.
Planned maintenance
Node maintenance
If you take a node down for maintenance, package failover and quorum calculation is based on
the remaining nodes. Make sure that the nodes are taken down evenly at each site, and that
enough nodes remain on-line to form a quorum if a failure occurs. Planned maintenance is treated
the same as a failure by the cluster.
Metrocluster package maintenance
There might be situations when the package needs to be taken down for maintenance purposes
without moving the package to another node. The following procedure is recommended for normal
maintenance of the Metrocluster with Continuous Access EVA:
1. Disable packge switching.
# cmmodpkg -d <pkgname>
2. If SMI-S user credentials or ports are being changed, update the smis.conf file and
re-generate the caeva.map file. Distribute the updated caeva.map file to all the nodes of
the cluster.
3. If there are changes to the package attributes, edit the configuration file, and then apply the
updated package configuration.
# cmapplyconf -P <pkgname.config>
4. Start the package with the appropriate Serviceguard command.
# cmmodpkg -e <pkgname>
Failback
If the primary site is restored after a failover to the recovery site, you may want to fail back the
package to the primary site. Manually resync the data from the recovery site to the primary site.
After resynchronization is complete, halt the package on the recovery site, and restart it on the
primary site. Metrocluster performs a failover of the storage, which returns the SOURCE status to
the primary VDisks.
Administering the SADTA configuration
This section elaborates the procedures that need to be followed to administer a SADTA configuration.
Cluster Node Maintenance
To perform maintenance procedures on a cluster node, the node must be removed from the cluster.
Run the cmhaltnode -f command to move the node out of the cluster. This command halts the
complex workload package instance running on the node. When there are other nodes in the site
and the Site Controller Package is still running on the site, the site aware disaster tolerant workload
continues to run with one less instance on the same site.
Administering the SADTA configuration 61